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现代地质 ›› 2021, Vol. 35 ›› Issue (05): 1155-1177.DOI: 10.19657/j.geoscience.1000-8527.2021.107

• 岩石学 • 上一篇    下一篇

扬子板块西缘中生代—新生代碰撞造山事件的记录:来自峨眉山玄武岩的锆石U-Pb同位素证据

张宏辉1(), 袁永盛1(), 余杨忠1, 李鸿1, 张沥元2, 李致伟1, 郭太堂1, 潘江涛1, 詹华思3, 石海涛4   

  1. 1.中国地质调查局昆明自然资源综合调查中心,云南 昆明 650100
    2.中国地质调查局地球物理调查中心,河北 廊坊 065000
    3.中国地质调查局海口海洋地质调查中心,海南 海口 571127
    4.中国地质调查局乌鲁木齐自然资源综合调查中心,新疆 乌鲁木齐 830000
  • 收稿日期:2021-07-07 修回日期:2021-08-21 出版日期:2021-10-10 发布日期:2021-11-04
  • 通讯作者: 袁永盛
  • 作者简介:袁永盛,男,工程师,1989年出生,资源勘查工程专业,主要从事岩浆岩、地层学方面的研究工作。Email: 879933153@qq.com
    张宏辉,男,工程师,1989年出生,资源勘查工程专业,主要从事区域地质调查工作。Email: 673872084@qq.com
  • 基金资助:
    中国地质调查局项目“重要矿产资源调查评价”子项目“云南乌蒙山西部甸尾街、沧溪、马街、朵马戛幅 1:50 000区域地质矿产调查”(DD2016008001)

Records of Mesozoic-Cenozoic Collision Orogenic Events on the Western Margin of the Yangtze Platform:Geochronology Evidence from Zircon U-Pb Isotope of Emeishan Basalt

ZHANG Honghui1(), YUAN Yongsheng1(), YU Yangzhong1, LI Hong1, ZHANG Liyuan2, LI Zhiwei1, GUO Taitang1, PAN Jiangtao1, ZHAN Huasi3, SHI Haitao4   

  1. 1. Kunming Natural Resources Comprehensive Investigation Center of China Geological Survey,Kunming,Yunnan 650100, China
    2. Geophysical Investigation Center of China Geological Survey,Langfang,Hebei 065000,China
    3. Haikou Marine Geological Investigation Center of China Geological Survey,Haikou,Hainan 571127,China
    4. Urumqi Natural Resources Comprehensive Investigation Center of China Geological Survey,Urumqi,Xinjiang 830000, China
  • Received:2021-07-07 Revised:2021-08-21 Online:2021-10-10 Published:2021-11-04
  • Contact: YUAN Yongsheng

摘要:

利用LA-ICP-MS测定技术,对扬子板块西缘滇东倘甸一带的峨眉山玄武岩中的锆石进行了U-Pb同位素年龄测定,363个年龄数据的分布范围为(14.9±0.6)~(3 023±50) Ma,跨越地质时代长,其11个年龄峰值为750~850 Ma、~450 Ma、~275Ma、~260 Ma、~247 Ma、~215 Ma、~160 Ma、~120 Ma、~100 Ma、~52 Ma及~35 Ma,反映了峨眉山玄武岩在形成过程中经历地壳物质的混染,形成后受到了后期构造热事件的巨大影响。其中峨眉山玄武岩一、二亚旋回分别形成于(259.9±3.2) Ma及(259.2±3.6) Ma,~275 Ma的玄武岩锆石年龄可能代表峨眉山玄武岩岩浆房的形成年龄及峨眉地幔柱事件导致地壳开始隆升的时间,峨眉山玄武岩形成后,扬子板块西缘依次经历了~247 Ma、~215 Ma、~160 Ma、~120 Ma、~100 Ma、~52 Ma、~35 Ma的构造热事件,这些年龄数据是扬子板块西缘中生代—新生代碰撞造山事件达到温压高峰的时间记录。

关键词: 峨眉山玄武岩, 锆石U-Pb年龄, 碰撞造山, 扬子板块西缘, LA-ICP-MS

Abstract:

Using LA-ICP-MS technique,the U-Pb isotope determination of zircons in the Emeishan basalts in Tangdian, of eastern Yunnan on the western margin of the Yangtze Plate is carried out. The distribution range of 363 age data is (14.9±0.6)-(3,023±50) Ma, spanning a long geological age, its 11 age peaks are 750~850 Ma, ~450 Ma, ~275 Ma, ~260 Ma, ~247 Ma, ~215 Ma, ~160 Ma, ~120 Ma, ~100 Ma, ~52 Ma and ~35 Ma, respectively, reflecting that Emeishan basalt experienced the contamination of crustal materials in the formation process, and being affected by later tectonic thermal events. The first and second sub-circle of the Emeishan basalt were formed at (259.9±3.2) Ma and (259.2±3.6) Ma, respectively. The zircon ages of the basalts of ~275 Ma may represent the age of the formation age of Emeishan basalt magma chamber and the time when the crust began to uplift due to Emei mantle plume event.After the formation of the Emeishan basalt, the western margin of the Yangtze Plate experienced successively tectonic thermal events of ~247 Ma, ~215 Ma, ~160 Ma, ~120 Ma, ~100 Ma, ~52 Ma, and ~35 Ma. These age data are the time records of the Mesozoic Cenozoic collision orogenic event reaching the peak of temperature and pressure on the western margin of the Yangtze Plate.

Key words: Emeishan basalt, zircon U-Pb age, collision orogeny, west margin of Yangtze Plate, LA-ICP-MS

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